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Lyude Paul fde7266fb2 drm/i915: Fix eDP DPCD aux max backlight calculations
Max backlight value for the panel was being calculated using byte
count i.e. 0xffff if 2 bytes are supported for backlight brightness
and 0xff if 1 byte is supported. However, EDP_PWMGEN_BIT_COUNT
determines the number of active control bits used for the brightness
setting. Thus, even if the panel uses 2 byte setting, it might not use
all the control bits. Thus, max backlight should be set based on the
value of EDP_PWMGEN_BIT_COUNT instead of assuming 65535 or 255.

Additionally, EDP_PWMGEN_BIT_COUNT was being updated based on the VBT
frequency which results in a different max backlight value. Thus,
setting of EDP_PWMGEN_BIT_COUNT is moved to setup phase instead of
enable so that max backlight can be calculated correctly. Only the
frequency divider is set during the enable phase using the value of
EDP_PWMGEN_BIT_COUNT.

This is based off the original patch series from Furquan Shaikh
<furquan@google.com>:

https://patchwork.freedesktop.org/patch/317255/?series=62326&rev=3

Changes since original patch:
* Remove unused intel_dp variable in intel_dp_aux_setup_backlight()
* Fix checkpatch issues
* Make sure that we rewrite the pwmgen bit count whenever we bring the
  panel out of D3 mode

v2 by Jani:
* rebase
* fix readb return value check

Cc: Furquan Shaikh <furquan@google.com>
Tested-by: AceLan Kao <acelan.kao@canonical.com>
Tested-by: Perry Yuan <pyuan@redhat.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200116211623.53799-2-lyude@redhat.com
2020-01-17 13:41:00 +02:00
arch Merge drm/drm-next into drm-intel-next-queued 2020-01-09 17:19:12 +02:00
block for-linus-20191212 2019-12-13 14:27:19 -08:00
certs certs: Add wrapper function to check blacklisted binary hash 2019-11-12 12:25:50 +11:00
crypto treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
Documentation dt-bindings: fix warnings in xinpeng,xpp055c272.yaml 2020-01-06 19:43:40 +01:00
drivers drm/i915: Fix eDP DPCD aux max backlight calculations 2020-01-17 13:41:00 +02:00
fs Merge branch 'remove-ksys-mount-dup' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux 2019-12-15 11:36:12 -08:00
include Merge drm/drm-next into drm-intel-next-queued 2020-01-09 17:19:12 +02:00
init fs: remove ksys_dup() 2019-12-12 19:00:36 +01:00
ipc treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
kernel treewide conversion from FIELD_SIZEOF() to sizeof_field() 2019-12-13 14:02:12 -08:00
lib lib: raid6: fix awk build warnings 2019-12-09 18:55:03 +01:00
LICENSES
mm Merge branch 'akpm' (patches from Andrew) 2019-12-05 09:46:26 -08:00
net io_uring-5.5-20191212 2019-12-13 14:24:54 -08:00
samples drm-misc-next for v5.6: 2019-12-17 13:57:54 +01:00
scripts pr_warning() removal for 5.5 2019-12-09 11:48:21 -08:00
security treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
sound sound fixes for 5.5-rc2 2019-12-13 14:40:38 -08:00
tools drm-misc-next for v5.6: 2020-01-03 11:43:44 +10:00
usr arch: sembuf.h: make uapi asm/sembuf.h self-contained 2019-12-04 19:44:14 -08:00
virt KVM: Fix jump label out_free_* in kvm_init() 2019-11-23 11:29:17 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore modpost: dump missing namespaces into a single modules.nsdeps file 2019-11-11 20:10:01 +09:00
.mailmap Update mailmap info for Steve Wise 2019-12-09 13:49:25 -05:00
COPYING
CREDITS Linux 5.4-rc4 2019-10-29 04:43:29 -06:00
Kbuild
Kconfig
MAINTAINERS drm-misc-next for v5.6: 2019-12-17 13:57:54 +01:00
Makefile Linux 5.5-rc2 2019-12-15 15:16:08 -08:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
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In order to build the documentation, use ``make htmldocs`` or
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    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.